PET imaging of mGluR5 with drug challenge

Diseases and Conditions Researched

Major Depressive Disorder

What is the purpose of this trial?

This study is designed to look at that involvement of a process in the brain called the glutamate system in depression. Participants will undergo a screening session, up to two fMRI scans, and up to three PET scans, as well as cognitive testing at each scan session. For one of the PET scans, a drug (either ketamine or n-acetyl cysteine) will be administered.

Hypothesis 1: The investigators hypothesize administration of ketamine or n-acetylcysteine (NAC) will lead to a decrease in mGluR5.

Hypothesis 2: The investigators hypothesize an improvement in memory and attentional skills after drug challenge.

Score >16 on HDRS if currently depressed or <11 if not currently depressed

treatment or non-treatment seeking who understand that this study is for research purposes only

Inclusion criteria for healthy controls

no current, or history of, any DSM-IV diagnosis

no first-degree relative with history of psychotic, mood, or anxiety disorder

Exclusion Criteria:

Current or past significant medical, neurological, or metabolic disorder or loss of consciousness for 5 minutes or more

active, significant suicidal ideation

implanted metallic devices or any MR contraindications

women who are pregnant or breastfeeding

met DSM-IV criteria for alcohol/illicit substance dependence in their life-time or met alcohol/illicit substance abuse within past year

history of prior radiation exposure for research purposes within the past year such that participation in this study would place them over FDA limits for annual radiation exposure. This guideline is an effective dose of 5 rem received per year

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